1. Field of the Invention
The present invention relates to a method for forming an optical package structure, and the formed optical package structure. In particular, to a package structure having an optical barrier and the manufacturing method thereof. In the optical package structure, the optical barrier is completely disposed within the package material, having the advantages such as being compatible with traditional production methods.
2. Description of the Prior Art
With the development of portable electronic products, the application of touch screens becomes increasingly common. A touch screen is a touch-enabled display panel, such as a touch sensitive transparent panel surface. A touch screen allows the user using finger or stylus to touch the screen, and to select or to move the cursor. In order to conveniently use the touch screen, an optical sensor, such as an infrared light proximity sensor (IR proximity sensor), is widely used on the handheld communications device for detecting the user's face, and to achieve the control effect in operation.
Proximity sensors applied in handheld products can be used to control the on/off switch in certain functions. For example, when the user does not use the screen, the screen will be automatically locked, thereby extending battery life. On the other hand, when the user's head or face is close to the touch screen, the touch function is automatically locked, so as to prevent the head from inadvertently touching the screen. In addition, the detecting distance of the long-distance proximity sensors is about 20-80 cm.
A proximity sensor has at least one emitter and at least one detector. To avoid signal crosstalk, in a conventional process, one method is to use the packaging material to package the emitter and the detector respectively, and next, using the metal frame or plastic cap to assemble the package structures mentioned above, used as the barrier structure having signal isolated functions. Besides, the traditional emitter has a larger emitting angle, so in order to effectively shield the optical interference between the emitter and the detector, one method for resolving the issue is shown in FIG. 12A, which shows Taiwan patent publication No. I385364. As shown in FIG. 12A, a barrier 20 is disposed between the package structure 10′ and 30′, in other words, the barrier 20 disposed between the emitter 10 and the detector 30. Or on the other hand, as shown in FIG. 12B, which shows Taiwan patent publication No. I438405, a barrier 20 such as a plastic or metal cap covers the package structure 10′ and 30′, so as to isolate the emitter 10 and the detector 30, thereby preventing the leakage light.
Another method involves after encapsulating the emitter and the detector respectively, then cutting along the perimeter of each sensor area to form the cutting path, said cutting path isolating the emitter and the detector. Or furthermore, forming the spacers on the cutting path of an exposed substrate, therefore the spacer will be disposed outside of the packaging materials. However, the method not only increases the process time, but since the spacers need additional space for accommodating them, the minimum package structure is hard to achieve.
With the trend for reducing elements' volume, all of method for forming the metal frame, plastic cap, cutting path or spacer, need high accuracy between those elements and the packaged structure, so as to form a high isolation effect sensor unit, thus greatly increasing the difficulty of the process, and also preventing the product yield from being effectively improved.